2024-07-28 08:58:39
Some sunscreen filters are toxic to coral reefs. Other forms of nanoparticles can cross biological membranes, raising questions about their harmfulness. So should we choose UV-protective clothing with a protection level equivalent to SPF 50 sunscreen lotion?
After a sad and rainy few months, the sun finally arrives, and with it comes those famous ultraviolet (UV) rays that we must be wary of. In fact, excessive UV rays attack skin cells and can cause irreversible damage, such as the development of skin cancer.
according to National Cancer InstituteThe number of new skin cancer cases doubled between 1990 and 2023.
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Chemical and physical filters, the “barrier” to sunscreen
When we talk about sun protection, we usually think of sunscreen. But how exactly do they work?
Before continuing, a recap UV Components. Sunlight contains three types of ultraviolet rays: UVA, UVB and UVC. All UVC and most UVB are absorbed by the ozone layer as they pass through the atmosphere. Only UVA is not effectively filtered by the atmosphere and accounts for 95% of the UV rays that reach the earth’s surface.
UVA has long-term effects and plays an important role in causing premature aging of the skin and increasing the risk of skin cancer. UVB rays reach the epidermis and cause sunburn and tanning in the short term. However, in the long term, their cumulative effects can also lead to premature skin aging and the appearance of cancer.
sunscreen lotion Blocks UV rays before they penetrate the skin. It contains two types of UV filters: chemical (organic) filters and physical (mineral) filters.
Organic filters (molecules containing carbon atoms) absorb UV rays instead of the skin and convert the received radiant energy into low-level heat, which is then dissipated.
The advantage of these filters is that they are transparent once applied to the skin. However, organic filters are not always effective for all wavelengths of the UV spectrum. In order to obtain adequate protection, Often they need to be combined. Therefore, the ingredients of a sunscreen product may contain several complementary chemical molecules, as shown on the label.
Mineral filters act as a physical barrier by reflecting UV rays off the skin, a bit like a mirror. These filters are primarily made of oxides such as zinc oxide and titanium dioxide. The advantages of mineral filters are Less allergenic and more active at all wavelengths, superior to organic filters in all UV wavelength ranges. However, they often form an unsightly white film on the skin.
Additionally, some of these mineral screens are controversial due to the nanoparticle form they are formulated in (to avoid a white appearance on the skin). We will return to this point later.
How much UV rays escape sunscreen?
In both cases, as the name suggests, these solar filters act as a “screen” and do not block all of the sun’s UV rays. Some of these rays can pass through sunscreen and enter our skin. To measure the amount of UV rays escaping from sunscreen, we use sun protection factor, or SPF (note that the English abbreviation SPF is sometimes displayed on the packaging). The higher the SPF, the less UV rays pass through the sun filter.
and it is applied correctly (In terms of quantity and frequency), according to statistics, a sunscreen with an SPF of 15 absorbs 93% of UVB, while a sunscreen with an SPF of 30 filters 97% of UVB. European Commission recommendations. Finally, the level of protection between SPF 30 and SPF 50 sunscreen products (Blocks 98% of UVB) will end up being very close…
However, although sunscreen is very effective under optimal conditions of usetheir effectiveness decreases over time and varies according to several parameters, such as the amount of cream applied, the friction of removing the cream, sweat, water, etc.
Some chemical filters are toxic to corals
On the other hand, multiple scientific studies show that sunscreen is not environmentally neutral. In fact, UV filters have harmful and aggressive effects on coral reefs and contribute to coral reef bleaching.
In France, overseas corals in Guadeloupe, Martinique, Reunion and Mayotte are also affected. After reviewing the scientific literature on the issue with the support of the French Biodiversity Office, the National Agency for Health Security (ANSES) stated Toxicity of three UV filters to corals Found in sunscreen lotions. They are oxybenzone, methacrylic acid, and octocrylene.
How to identify sunscreen that respects the marine environment? The ANSES service warns against pictograms or statements emphasizing respect for the marine environment on certain sunscreen lotions:
“These labels must be supported by research conducted responsibly by the manufacturer selling them. Presence of one of the above substances [l’oxybenzone, l’octinoxate et l’octocrylène] seems incompatible with the possibility of benefiting from such claims. »
In practice, therefore, the solution involves checking the ingredients list of your sunscreen to see if it does not contain one of these three UV filters.
What are the health risks of mineral filters in the form of nanoparticles?
Sunscreen, especially due to the presence of nanoparticles (titanium dioxide, zinc oxide), also raises questions about our health.
Nanoparticles are very small particles, less than 100 nm in size (i.e. 10,000 times smaller than a raspberry seed). Their use in sunscreen improves product absorption and reduces the “white” effect on the skin. In short, they provide the comfort and aesthetics that are sought after and even requested by consumers, many of whom are hesitant to use “white paste.”
The problem with these nanoparticles is their ability to cross biological membranes. Today, science doesn’t know much about their impact on our health. However, different studies agree that using sunscreen containing titanium dioxide is safe for healthy skin, but not Suitable for people with damaged skin or skin diseases.
UV-protective clothing to protect yourself from the sun
So, are clothes a substitute? Be careful, not just any summer outfit will do the trick… A regular white T-shirt made of lightweight cotton transmits 20% of UV rays. This can give a feeling of protection, but burns can occur more or less quickly According to photo type people.
Additionally, when it gets wet, its effectiveness is further reduced. On the other hand, there are also UV-protective clothing specifically designed to protect against the sun’s UV rays.
The UV resistance of clothing depends in particular on:
Its color (bright or dark blocks UV rays best)
the weave of the textile (cotton with a breathable weave is less protective than polyester with a denser weave) and
Add additives that reduce UV penetration (e.g. ceramic particles).
Best UV protection: combine the right textiles and sunscreen
As with sunscreen, the UV protection of this type of clothing is determined by a metric called UPF (Ultraviolet Protection Factor), which measures the proportion of UV rays blocked.
When UV protective clothing is on display FPU 50+, meaning they block over 98% of UV rays (like 50 times more sunscreen). You should still remember to replace your UV-protective clothing regularly (ideally every new season), as their effectiveness decreases as they wear out or stretch.
On the other hand, even when wearing high UPF clothing, not all parts of the body are protected, especially the face. Therefore, it is recommended to protect them The right sunscreen. Also, wearing a wide-brimmed hat and sunglasses is highly recommended.
Ultimately, to effectively protect yourself from the sun, there’s nothing better than…a little shade.
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